1 /* 2 * Copyright 2018 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkFontPriv_DEFINED 9 #define SkFontPriv_DEFINED 10 11 #include "include/core/SkFont.h" 12 #include "include/core/SkMatrix.h" 13 #include "include/core/SkTypeface.h" 14 15 class SkReadBuffer; 16 class SkWriteBuffer; 17 18 class SkFontPriv { 19 public: 20 /* This is the size we use when we ask for a glyph's path. We then 21 * post-transform it as we draw to match the request. 22 * This is done to try to re-use cache entries for the path. 23 * 24 * This value is somewhat arbitrary. In theory, it could be 1, since 25 * we store paths as floats. However, we get the path from the font 26 * scaler, and it may represent its paths as fixed-point (or 26.6), 27 * so we shouldn't ask for something too big (might overflow 16.16) 28 * or too small (underflow 26.6). 29 * 30 * This value could track kMaxSizeForGlyphCache, assuming the above 31 * constraints, but since we ask for unhinted paths, the two values 32 * need not match per-se. 33 */ 34 static constexpr int kCanonicalTextSizeForPaths = 64; 35 36 /** 37 * Return a matrix that applies the paint's text values: size, scale, skew 38 */ MakeTextMatrix(SkScalar size,SkScalar scaleX,SkScalar skewX)39 static SkMatrix MakeTextMatrix(SkScalar size, SkScalar scaleX, SkScalar skewX) { 40 SkMatrix m = SkMatrix::MakeScale(size * scaleX, size); 41 if (skewX) { 42 m.postSkew(skewX, 0); 43 } 44 return m; 45 } 46 MakeTextMatrix(const SkFont & font)47 static SkMatrix MakeTextMatrix(const SkFont& font) { 48 return MakeTextMatrix(font.getSize(), font.getScaleX(), font.getSkewX()); 49 } 50 51 static void ScaleFontMetrics(SkFontMetrics*, SkScalar); 52 53 /** 54 Returns the union of bounds of all glyphs. 55 Returned dimensions are computed by font manager from font data, 56 ignoring SkPaint::Hinting. Includes font metrics, but not fake bold or SkPathEffect. 57 58 If text size is large, text scale is one, and text skew is zero, 59 returns the bounds as: 60 { SkFontMetrics::fXMin, SkFontMetrics::fTop, SkFontMetrics::fXMax, SkFontMetrics::fBottom }. 61 62 @return union of bounds of all glyphs 63 */ 64 static SkRect GetFontBounds(const SkFont&); 65 IsFinite(const SkFont & font)66 static bool IsFinite(const SkFont& font) { 67 return SkScalarIsFinite(font.getSize()) && 68 SkScalarIsFinite(font.getScaleX()) && 69 SkScalarIsFinite(font.getSkewX()); 70 } 71 72 // Returns the number of elements (characters or glyphs) in the array. 73 static int CountTextElements(const void* text, size_t byteLength, SkTextEncoding); 74 75 static void GlyphsToUnichars(const SkFont&, const uint16_t glyphs[], int count, SkUnichar[]); 76 77 static void Flatten(const SkFont&, SkWriteBuffer& buffer); 78 static bool Unflatten(SkFont*, SkReadBuffer& buffer); 79 }; 80 81 class SkAutoToGlyphs { 82 public: SkAutoToGlyphs(const SkFont & font,const void * text,size_t length,SkTextEncoding encoding)83 SkAutoToGlyphs(const SkFont& font, const void* text, size_t length, SkTextEncoding encoding) { 84 if (encoding == SkTextEncoding::kGlyphID || length == 0) { 85 fGlyphs = reinterpret_cast<const uint16_t*>(text); 86 fCount = length >> 1; 87 } else { 88 fCount = font.countText(text, length, encoding); 89 fStorage.reset(fCount); 90 font.textToGlyphs(text, length, encoding, fStorage.get(), fCount); 91 fGlyphs = fStorage.get(); 92 } 93 } 94 count()95 int count() const { return fCount; } glyphs()96 const uint16_t* glyphs() const { return fGlyphs; } 97 98 private: 99 SkAutoSTArray<32, uint16_t> fStorage; 100 const uint16_t* fGlyphs; 101 int fCount; 102 }; 103 104 #endif 105